A brief and dispassionate note on 'GDP'

The book, not the concept. I've been reading "GDP: A Brief but Affectionate History." First, I should say I personally like brief and simple. Better than long, drown-out and complex. That's why I'm not sure why it's presumed that brief must somehow be antagonistic, and brevity should be tempered by affection. At any rate, I do like the GDP concept.

It measures material production, which is a key feature of capitalist economies, centered on the accumulation of material wealth. It was not designed to measure everything. Certainly not sustainability. Or happiness, for that matter. And although Diane Coyle, author of the book, suggests that it can't be used as a measure of well-being, GDP per capita is certainly employed as an index of welfare, even though no serious (I don't mean mainstream) economist would take GDP per capita as the only indicator of development. Finally, it isn't a measure of inequality, but functional income distribution, the shares of labor and capital compensation in total GDP, is actually one of the best measures of inequality. So yes, GDP does have its flaws (for an accessible discussion of the limitations of GDP go here, and for my views here).

Note that Kuznets apparently was against including government spending, in particular defense expenditures, as part of GDP, according to Coyle, since in his view it didn't increase well-being. That proposition is not uncontroversial. A lot of government spending, including in defense, is central for technological innovation, and, hence, for higher productivity growth and increasing living standards. The internet (as well as driverless cars and many other things) that I'm using to post this piece is the result of DARPA's investment -- the Defense Advanced Research Projects Agency, a defense department agency.

This suggests to me that we owe more to the British Keynesians, Richard Stone and James Meade, that basically created the methodology of of the National Accounts during World-War-II, than to Kuznets (all three won the Sveriges Riksbank Prize, by the way, but Meade's wasn't related to national accounting). And, in a sense, it is what Coyle suggests when she argues that:

“It [Keynesian economics] became the basis for a more interventionist approach to government economic policy from the 1940s onward, using both fiscal policy (the level of tax and spending) and monetary policy (the level of interest rates and availability of credit) to target a higher and less volatile rate of growth for the economy. The use of these tools was developed more fully by other economists after Keynes’s early death in April 1946. Postwar policymakers still bore the scars of the Great Depression and pounced on the economic theories of Keynes and his successors as a means of averting a repetition of that crisis. Crucially, the development of GDP, and specifically its inclusion of government expenditure, winning out over Kuznets’s welfare-based approach made Keynesian macroeconomic theory the fundamental basis of how governments ran their economies in the postwar era. The conceptual measurement change enabled a significant change in the part governments were to play in the economy. GDP statistics and Keynesian macroeconomic policy were mutually reinforcing. The story of GDP since 1940 is also the story of macroeconomics. The availability of national accounts statistics made demand management seem not only feasible but also scientific.”

This is essentially correct, yet it might be misinterpreted as suggesting that the National Income and Product Accounts (NIPA) are intrinsically Keynesian, as some far right supply-siders have argued. Nothing in the NIPA implies that causality goes from autonomous spending to income, as in Keynes' Principle of Effective Demand, and the accounts are compatible with a model based on Say's Law (not that I personally think that's a good idea).

It only means that by the time the National Accounts were developed, a version of Keynesian economics, as it turns the Neoclassical Synthesis, had more or less become the mainstream interpretation of how the macroeconomy works. The same is true of say econometrics, and macro econometric models, like the Klein-Goldberger, which was Keynesian, and would not lead a reasonable person to conclude that econometrics is Keynesian (Keynes was, in fact, skeptical about it).

Lawrence Klein author of The Keynesian Revolution has passed away

Lawrence R. Klein (1920-2013)

Lawrence Klein, of Klein-Goldberger US econometric model fame, and author of The Keynesian Revolution (here the Google Books link), and winner of the Sveriges Riksbank Prize in Memory of Alfred Nobel in 1980, has passed away. Klein was a Neoclassical Synthesis Keynesian (often referred to as Old Keynesian now, to distinguish him from the New Keynesians) that made his contribution by developing the empirical applications of the Keynesian model for the US economy.

The seminal work was done in the late 1940s and early 1950s in the context of the Cowles Commission. His book An Econometric Model of the United States, 1929–1952 was further developed in 1955 with his co-author (Arthur Goldberger), published as An Econometric Model of the United States 1929–1952, introduced the celebrated Klein-Goldberger model. The Cowles Commission Model still lives in Ray Fair's macro-econometric model, that maintains essentially the same methodology, resisting to the Lucas critique and the Dynamic Stochastic General Equilibrium (DSGE) models of the Real Business Cycle School (RBC) and their New Keynesian alternatives.

It must be noted that in Klein's original model, expectations did not play a role, since it was complicated to incorporate those, interest rates did not have an impact on investment (basically adopting an accelerator) and that wealth effects (which allow for the Pigou effect, and the return to full employment) on consumption were also absent. So in a sense his model did differ, because of the need to adapt to economic data, from the theoretical versions of the Neoclassical Synthesis, and was closer to heterodox interpretations of Keynes.

Hydraulic Krugman on Wynne Godley

Paul Krugman commented on the NY Times piece on Wynne. There are many little incorrect interpretations, which derive from his lack of understanding of the history of ideas. First, he equates Wynne's model with the old hydraulic Keynesianism (i.e. Neoclassical Synthesis) of Phillips (of Phillips curve fame, but also of the hydraulic model of the British economy). Nothing further from the truth.

Wynne came to economics via P. S. W. Andrews, one of his two most influential teachers at Oxford (the other being being Isaiah Berlin). Andrews and the full cost price authors that were part of the Oxford Economists' Research Group (OERG), under the leadership of Roy Harrod, and were in general more concerned with practical applications than with theoretical first principles. That influenced the way Wynne developed his skills as a modeler at the British Treasury, before being taken by Nicholas Kaldor, to head the Cambridge Department of Applied Economics (DAE), where he built together with Francis Cripps the Cambridge Economic Policy Group (CEPG).

Note that conventional hydraulic models, including the sort of Cowles models like the Klein-Goldberger model of the US economy, put great emphasis on the estimation of parameters based on certain simplistic macro behavior. Wynne took a very different approach to modeling than Klein-Goldberger. He was more concerned with what he referred to as 'model architecture' than with parameter estimation.

The architecture, which was careful about stock-flow consistency, showing that everything came from somewhere and went somewhere so to speak, also imposed a clear causality structure, which determined most of the results. In fact, Wynne believed that significant variations of the parameters might not greatly influence the end result of the model, which was used for simulations and scenarios that helped to understand how the economy functioned, rather than for strictly forecasting purposes.

Krugman then says these models were abandoned because they failed in the face of the Great Inflation of the 1970s, and because they did not deal with consumption in a coherent way. Here again he is wrong. First of all, Wynne's models had no trouble dealing with the inflation of the 1970s, correctly pointing out the effects of oil prices, devaluation, and wage pressures from the cost side rather than demand pull views, and he was one of the few that correctly foresaw the big recession that the Thatcher policies would cause.

On consumption the notion that Friedman somehow is better than Duesenberry and the relative income approach of other old Keynesians goes to show how limited is Krugman's understanding of his own tradition in the field (for more go here). Note that he believes that New Keynesians are just grafting a more sophisticated behavioral decision making approach to old Keynesian stories, without owing up to the limitations that the Old and New Keynesian models, based on rigidities and imperfections to avoid the tendency to the natural rate.

Wynne's model, in the Kaldorian tradition, with a supermultiplier determining growth, and with the Oxford pricing tradition determining prices, was free of the main limitations of the Hydraulic tradition to which Krugman belongs, whether he understands it or not. That is why Jonathan Schlefer, from the NY Times, is correct in suggesting that rebuilding macro on the basis of Wynne's work would make more sense.

On a funny note at the end, Krugman reveals his misconception about the role of old ideas in the history of science, and economics in particular. He says: "it is kind of funny to see a revival of old-fashioned macro hailed, at least by some, as the key to a reconstruction of the field." In his view, old ideas are only relevant if you can formalize them in modern garb, but are not a source of forgotten and incorrectly discarded knowledge that are better prepared to understand how the economy works. The limitations of the 'great economists' of today, make the loss of economists like Wynne all the more painful.

PS: Full disclosure, I'm quite biased on this topic, having worked for Wynne at the Levy Economics Institute for two years in 1997-98.

PS': Two additional posts by Unlearning Economics and Philip Pilkington and a link by Lars Syll (h/t for the link to Unlearning).